1. Field of the Invention
The present invention relates to a method for forming a coating film on a facet of a semiconductor optical device.
2. Description of the Related Art
Japanese Unexamined Patent Application Publication No. 2007-123374 discusses a method for forming a coating film on an end facet of a laser diode (LD) bar. In the coating-film forming method discussed in this document, a multilayer semiconductor structure including an active layer is first formed on a semiconductor substrate. Next, the semiconductor substrate is cleaved so that LD bars are formed. Subsequently, the LD bars are arranged with their cleaved facets facing upward, and spacers are disposed between the neighboring LD bars. Then, a coating film is formed on the cleaved facet of each LD bar. The thickness of each spacer is smaller than or equal to the width of each LD bar in the direction perpendicular to the cleaved facet.